In operating a conventional car brake system in case of emergency situation, a car driver may immediately tread the brake pedal at a great force, trying to stop the car right away. However, the output pressure of the brake hydraulic oil is very high, thereby suddenly locking the car wheels. Even the car wheels are locked, the great force of inertia of a car under high running speed may still cause slipping of the car or even turn over the car, possibly causing a serious traffic accident or injury especially on a rainy or snow day.
The present inventor has found such phenomena and invented the present vehicle brake system having means for preventing the locking of braked car wheels.